there is no perfect way as all can be cheated if you really want, that s why we do not accept when there are any doubt. So the point is to take away any doubts
- First of all: make pictures! Digital or slide or both. Video is great too.
- Make sure that the picture shows you, the summit marker and a typical view from the mountain. Take one to every side and do not just take a picture from below, showing your happy face against a blue sky background, those pictures could have been taken anywhere.
- Try to get pictures taken by others, preferably also from strangers, either with or without them. See previous notes
- Always get (email) adresses and names of witnesses: guides/witnesses/teammates, so they can testify and send you their images.
- register with any park services, try to get certificates when climbing with a commercial team etc.
- Do not leave anything on the summit, it thrashes nature. But do check for a summit book, sometimes hidden in a metal box or cannister, often a few meters away, and sign it clearly with date, time and your name.
Most of all: enjoy your climb